FIG. 1 is a diagram illustrating a pre-existing active diode circuit, and FIG. 2 is a diagram illustrating an example of forward turn-on caused by delays that may occur due to both a comparator and a gate driver, which are illustrated in FIG. 1.
An active diode includes a switch M1; and due to MOSFET properties, a parasitic diode D1 is placed between a drain and a source. When VKA, which is the voltages at the opposite ends of the parasitic diode D1, i.e., the voltages at cathode K and anode A, turns negative so that D1 is turned on, the active diode detects this point in time and turns on the switch M1 to reduce conduction loss. However, as can be seen in FIG. 2, if there is a case where delays have occurred due to both a comparator 10 and a gate driver 20 are long, as illustrated in FIG. 2, a section where M1 is turned on may be created even though VKA has been turned to (+). Here, a forward turn-on of the active diode occurs, which leads to unnecessary consumption of power. If a control circuit has been designed to have minimal delays, the section duration of the forward turn-on may be reduced; however, some inevitable delays do occur, and if a VKA signal is very fast, the problem caused by the delays may be greater.
In other words, in the case a high-speed input signal is processed using the active diode, the active diode is turned on due to the delay of the control signal controlled caused by the comparator 10, the gate driver 20, etc. even when the active diode should be turned off, thus resulting in the forward turn-on of the active diode. Such properties are what lead to unnecessary consumption of power